MERCES
Dynamic food web models reveal potential effects of
ecosystem restoration
MERCES final meeting 10th-11th November 2020 Sabine Horn and Marta Coll
WP5
MERCES
Food web modelling
• Quantitative (marine) ecosystem modelling (MEM) approach
• Tracking path of energy through food web components
• Different methodologies -> Ecopath with Ecosim and Ecospace
• Dynamic (spatial-) temporal model
• Includes environmental data and human activities
• Trophic and non-trophic interactions
• Future scenarios of change
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Modelling habitat-forming species
a) With mediation
X
a) Without mediation
b) Without mediation
HABITAT ROLE HABITAT CHANGE
Prey vulnerability
Seagrass abundance
(-) (+
)
Positive ecological
relationships (e.g. mediation) are parameterized using fieldwork data to model key interactions between species, considering density-
dependencies.
▪ Non-trophic interactions of HFS are essential and need to be included in model (mediation)
▪ HFS provide key services and functions
▪ When HFS are degraded, their roles erode and can even disappear
▪ Conservation and recovery of HFS essentiel to maintain key processes
MERCES
Three pilot case studies
http://agricultura.gencat.cat https://www.kelpex.org
Photo: Tobias Dolch
Kelp belts in Arctic Norway and deep sea
ecosystems
Coastal areas of the NW Mediterranean
Sea Seagrass meadows in
the Wadden Sea
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Influence of seagrass recovery on Wadden Sea ecosystem
•
Passive recovery of seagrass in northern part
•
Potential effects on ecosystem-level
•
Basic food web model of 1990s
•
Inclusion of mediation
•
Dynamic modelling over time
Wadden Sea Quality Status report, Dolch et al. (2018)
Horn et al. (in revision)
Predicted recovery effects
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Horn et al. (in revision)
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Conclusions from food web models
• Positive effect on consumers (more food)
• Mostly positive effects on inhabitants (enhanced protection)
• Indirect effects might influence trend
• Negative effect on inhabitants’ predators
• Mediation is important
• Results can differ from reality
• Effect on system functioning inconclusive
Horn et al. (in revision)
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Arctic deep sea ecosystem connected
to coastal kelp forests
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Predicted future cumulative effects
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Conclusion from food web models
• Kelp detritus from shallow coastal areas has a small but noticeable role structuring the deep-sea ecosystem
• Mediation is important to assess this role and future changes
• Depletion of kelp detritus can have noticeable impact on the deep-sea ecosystem structure
• The impact of climate change and cumulative effects of stressors will be large
• To assess the future changes of the Arctic deep-sea
ecosystems dependencies with adjacent ecosystems and cumulative effects are essential to be considered
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Coastal habitats of the NW
Mediterranean Sea
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Predicted recovery effects
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Conclusion from food web models
• Multi-zone MPAs advocated to reconcile conservation and fisheries
• The provision of both benefits is uncertain
• Our three MPAs in the NW Mediterranean Sea showed different ecological effectiveness
• Temporal increase of benefits were small with small recoveries of commercial and non-commercial species
• Currently testing spatial-temporal scenarios that include changes in protection, sustainable management of fisheries and HFS recovery to assess their potential
• Local data is scattered and scarce!
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Lessons learned in MERCES
• MEMs represent structure and functioning of ecosystems well
• Pilot studies show MEMs potential to assess the link between species recovery and ecosystem services
• Some gaps highlighted when focusing on restoration/recovery effects
• Need more knowledge on trophic and non-trophic links
• Response functions need to be developed with local knowledge
• Need field data on ecosystem services provided by HFS to validate modelling results
• We are facing the challenges ahead to further develop these case studies and link the recovery of HFS to ecosystem services and, in general, to a diversity of Nature-based solutions (NBS)
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References
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Thanks to:
Daniel Vilas Xavier Corrales Jeroen Steenbeek Torstein Pedersen Chiara Piroddi Tobias Dolch Harald Asmus
Thank you & close
Conference name, Date (e.g. 10 Dec 2012), Location
Marine Ecosystem Restoration in Changing European Seas (MERCES)
Grant agreement n. 689518
www.merces-project.eu
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 689518.
This output reflects only the author’s view and the European Union cannot be held responsible for any use that may be made of the information contained therein.
